Vapor generator



Jan. 9, 1945. M. FRlscH VAPOR GENERATOR Filed Nov.

INVENTOR Patented Jeni 9, 1945 ter Wheeler Corporation, NewYork, N. Y., a corporation of New York Application November 25, 1941, Serial No. 420,331

. v (Cl. 122-478) F This invention relates to vapor generators and 4 Claims.

more particularly pertains to apparatus for generating and superheating steam.

The invention provides a arrangement with which superheat control at all loads .on the generator is obtained. H l

The features and advantages which character ize the invention will be understood from the following description considered in connection with the accompanying drawing forming a part thereof, and in which: i i i l Fig. l is a vertical sectional view of asteam generator embodying'the invention, and

Fig.2 isa horizontal sectional view taken on line 22 of Fig. 1.

The inner surface of the side wall ii is lined with vertical water wall tubes 36 which extend ultiple furnace liperheating steam generator of novel and compact.

Referring to the drawing, the steam generator 3 illustrated has vertical refractory side walls II and. I2, a rear wall l3, 9. front wall not shown,

and roof portions 4 and I5. Adjacentthe roof portion I5 is a steam andwater drum l6, and between the roof portions l4 and I5 isa flue gas outlet Within the setting are two spaced furnaces |8 and I9 which are disposed adjacent w the side walls Hand l2 respectively. The inner f boundary of the furnace I8 is defined by a Verl tical bafile wall which extends upwardly from the lower portion of the setting and terminates short of the roof to provide a gas outlet 2| in the upper portion of the furnace. The innerboundary of thefurnace I9 is similarly defined by a vertical bafile Wall 22 which terminates short of the roof to provide agas outlet 23 inthe upper portionof the furnace. A stoker 24 to which fuel is supplied from a hopper 25 fires the furnace l8, anda stoker 26 towhich fuel issupplied from a a hopper 2'! and operated independently of vthe stoker 26, fires the furnace l3. The stokers .24 and 26 discharge into suitableash pits 28 and 29 respectively. Extending between the upper drum l6 and a lower drum 30, parallel to theupper drum, is a vertical bank of steam generating tubes 3| which are swept by the gases flowing from the furnace H) to the flue gas outlet through vertical, substantially parallel gas passages 32 and 33 which are connected in series. Passage 32"is formed betweenbaflle 22 and a baffle 34 which extends downwardly from drum It to a point short of the drum 3!), and communicates with the fur.

nace l9 through gasioutlet 23 and with the pas sage 33 at its lower end. Passage 33 is formed betweenb alfe 34 and a baffle 35 at the opposite side of the tube bank 3| which extends upwardly y from drum 30 and terminates short of the drumli; i

across the upper end of the setting and are connected at their upper ends to the drum. IS, the lower ends being connected to header 31 which is supplied with circulating water by suitable ex .ternal downcomer connections, not shown. The

im ersurface of the side wall I2 is similarly lined with vertical water wall tubes 33 which are connected at their upper ends to the drum |6,and

at their lower ends to header which is connected into the boiler circulation. The furnace side of the baffle wall 22 is lined by vertical water wall tubes 42 which extend to the drum l6 from lower header 43 which is connected into the boiler circulation. Adjacent/the gas outlet 23 the tubes 42 are spread apart to provide a passage for the gases. It willbe understood that the inner surfaces of the front and rear Walls are lined with water wall tubes, not shown, which are connected into the boiler circulation. 1

Inthe form shown, a combination radiant and V convection superheater isutilized and is. so arranged and disposed that it is subject to the heat of the gases produced in one furnace only. In the superheater furnace 8, the furnace side of thebaffie, wall 20 is lined with vertical radiant 5 connected to the-steam space of the drum IS in two spaced longitudinal rows, conduct steam downwardly in one pass to a lower header 49 from which the steam flows upwardly in one pass through the tubes 48 to a point adjacent the top of a baffle wall 50 which extends downwardly from the roof I 4 of the setting in spaced relationship to the baffle 20 to a point above the drum 3!) to form a gas passage 5| which is in communication at its upper end with furnace l3 through passage 2|. Adjacent the top of the baffle wall 50, the tubes 48 of the superheater pass through the baffle 50 and are formed into a plurality'of return bend loops of a convection superheater section 52, which is vertically disposed in th space between the baffles 50 and 35 forming a gas passage for thegases flowing from the furnace l8 and through the passage 5| to the flue gas outlet As shown, the tubes 48 of the radiant heat superheater section and. the tubes of the convection section 52; which are arranged for series now stant superheat temperature.

of steam therethrough, are continuous with each other, and no intermediate header connections are required. The elements of the convection superheater section 52 are connected to a superheater outlet header 53 which is fixed in position below the drum 30 and from which the superheated steam is conducted to the point of use.

In operation, the gases produced in the saturated steam furnace l9 flow upwardly through downwardly through passage 32 and upwardly through passage 33 over the steam generating tubes 3| to the outlet ll. Saturated steam is conducted from the upper drum it and fiows downwardly through superheater tubes 4! and ly into said gas outlet, means forming a plurality upwardly through tubes 48, mainly in radiant heat exchange relationship with the gases pro -f duced in the superheater furnace it. From the radiant section of the superheater, the steam flows through the convection section 52 in con vection heat exchange relationship with the gases flowing from the. furnace it through outlet 2!, downwardly through passage 55 and upwardly overthe convection section 52 and out the outlet H. The quantity of steam produced will be determined largely by the rate at which the furnace I9 is fired, although some steam will be generated in the water walls of the furnace. l8. Inasmuch as the gases produced in the saturated steam fur nace l 9 do not fiow in heat exchange relationship with the superheater, the degree to which the "steam is superheated will be determined by the degree to which the superheater furnace I8 is Y radiant heat and convection superheater employed, contribute to the maintenance of a con- With this arrangement, it will be observed that the steam flow in the convection section of the superheater is from the side near the wall 50 to the side near the steam generating section. Thus the superheater elements at the highest steam temperature are not subjected to the highest temperature gases flowing from the furnace l8 through outlet 2!. Since the superheater sections are shielded from the gases leaving one of the furnaces, the steam generator may be started up by firing that furnace only, thus eliminating any necessity for flooding the superheater during starting up periods. This considerably shortens the time ordinarily required to bring the unit onto the line. Also, if a feed water heater were out of service, a constant steam temperature can be maintained without-the use of a bypass or any other means of 'superheat-control except for the differential firing provided. The elimination of intermediate header connections between the radiant and convection sections of the superheater simplifies and reduces the cost of construction of the superheater and reduces the pressure drop, although intermediate headers may be employed, if desired.

It will be understood that changes may be made in the form, location and relative arrangeof the invention. Consequently, the invention is not to be limited excepting by the scope of the appended claims.

What is claimed is: I

1. Vapor generating apparatus comprising a setting, spaced furnaces in the setting, means in the lower portion of eachfurnace for firing the furnace, each furnace having a gas outlet opening at its upper portion in communication with the space between the furnaces, the setting having agas outlet at its upper portion communicat-\ the furnace and out thereof through the outlet. e With said space, means forming a plurality of vertical, substantially parallel gas passages in said space connected in series and communicating with the gas outlet opening of one furnace and the gas outlet of the setting, vapor generating surface in the gas passage discharging directof other gas passages in said space communicating with the gas outlet opening of another furnace and the gas outlet of the setting, said other passages being vertical and substantially parallel and connected in series, and a superheater hav-' ing a part disposedin the other gas passage discharging directly into said gas outlet.

2. Vapor generating apparatus comprising a setting, spaced furnaces in the setting, means in the lower portion of each furnace for firing the furnace, each furnacehaving agas outlet opening at its upper portion in communication with the spaceloetween the furnaces, the setting having a gas outlet at its upper portion communicating with said space, means forming a plurality of vertical, substantially parallel gas passages in said space connected in series and communicating with the gas outlet opening of gone furnace and the gas outlet of the setting, vapor 'generating' surface in the gas passage discharging directly into said gas outlet,'means forming a plurality of other gas passages in said space communicating with the gas outlet opening of another furnace and the gas outlet of the setting, said other passages being vertical and substan tially parallel and connected in series, and a superheater havinga part thereof disposed adjacent a wall of said other furnace and another ing directly into 'said gas outlet.

3. Vapor generating apparatus comprisinga setting, spaced furnaces in the setting, means in the lower portion of each furnace for firing the furnace, each furnace having a gas outlet i opening at its upper portion in communication with the space between the furnaces, the'setting having a gas outlet at its upper portion communicating with said space, means forming two vertical, substantially parallel gas passages in said space connected at their lower end, the first passage communicating with the gas outlet opening of one furnace for flow of gases downwardly therein, the second passage communicating with the gas outlet of the setting for flow of the gases upwardly therein; vapor generating surface in the second gas passagegmeansforming two other vertical, substantially parallel 'g'as passages in, said space connected at their lower end, the first of the other passages-communicating with the gas outlet opening of another'furnace for the flow of gases downwardly therein, the second-of the other passages communicating with the gas butlet of the setting for flow of gases upwardly therein, and a superheater having a part thereof disposed adjacent a'wall of said other furnace and another part disposed in the second of the other gas passages.

4. Vapor generating apparatus comprising a part disposed in the other gas passage dischargsetting, spaced furnaces in the setting, a stoker for firing each furnace, each furnace having a gas outlet opening at its upper portion in com munication with the space between the furnaces,

the setting having a gas outlet at its upper portion communicating with said space, means forming two vertical, substantially parallel gas passages in said space connected at their lower end, the first passage communicating with the gas I outlet opening of one furnace for flow of gases downwardly therein, the second passage communicating with the gas outlet of the setting for flow of the gases upwardly therein, vapor generating surface in the second gas passage, means forming two other vertical, substantially parallel gas passages in said space connected. at their lower end, the first of the other passages communicating with the gas outlet opening of another furnace forthe flow of gases downwardly therein, the second of the other passages communicating with the gas outlet of the setting for flow of gases upwardly therein, and a super heater havinga part thereof disposed adjacent a wall of said other furnace and another part disposed in the second of the other gas passages.

MARTIN FRISCH. 

